This invention is related generally to decal laminate technology, such as is involved in the preparation of one or more decals (e.g., xe2x80x9cgraphic areasxe2x80x9d or xe2x80x9cproduct areasxe2x80x9d) which are formed as part of a removable layer of a laminate for later removal and application onto various surfaces. More particularly, the invention relates to the field involving prior removal of waste portions of removable laminate layers, leaving the removable decal in place on the laminate.
Many if not most decals are graphics-image-bearing portions (sometimes referred to herein as xe2x80x9cproduct areas,xe2x80x9d whether or not they have graphics images thereon) of a removable layer (sometimes referred to herein as a xe2x80x9cface layerxe2x80x9d) of a laminate. Each such decal laminate typically includes the face layer and a backing layer (or xe2x80x9clinerxe2x80x9d), the face layer being removably secured to the backing layer by an adhesive. The adhesive is preferential to the face layer, and is used, after removal of the product area(s) from the backing layer, for the adhesive attachment of the product area(s) of the face layer onto the surface intended to be coveredxe2x80x94for decorative, signage or any of a multitude of other purposes.
To facilitate production of product areas (decals) in a form ready for use, it is frequently necessary or desirable to pre-remove the area or areas of the face layer which is/are not product areas from the backing layer of the decal laminate. (These non-product areas of the face layer are often referred to herein as xe2x80x9cwaste areas.xe2x80x9d) Such pre-removal of waste areas leaves the product area(s) on the backing layerxe2x80x94ready to be easily peeled away from the backing layer just prior to use. The pre-removal of waste areas of a face layer, sometimes referred to xe2x80x9csheet-weeding,xe2x80x9d greatly facilitates the subsequent removal of product areas (decals) just prior to use.
(The pre-removal of waste areas, of course, follows slitting or other severing of the product areas from the waste areas, which occurs while the removable layer to be slit or severed is in place on the backing layer. A highly preferred and advantageous method and apparatus for accurate severing around the product area or areas of the face layer of a decal laminate is disclosed in commonly-owned U.S. patent application Ser. No. 09/678,594, filed Oct. 4, 2000, entitled xe2x80x9cMethod and Apparatus for Precision Cutting and the Like of Graphics Areas from Sheets.xe2x80x9d)
Sheet-weeding is typically carried out by nimble-fingered workers who delicately lift and peel away unused portions of the image-bearing face layer of a decal laminate. This is tedious and time-consuming work. Progress has been made toward automating the sheet-weeding process; despite such efforts, there remains a need for an improved automatic waste-area removal method and apparatus.
Various automated systems have been devised over the years for facilitating sheet-weeding operations. Among these are the systems and concepts disclosed in the following U.S. Pat. No. 5,143,576 (Logan); U.S. Pat. No. 5,277,736 (Logan); U.S. Pat. No. 5,026,584 (Logan); U.S. Pat. No. 4,246,058 (Reed); U.S. Pat. No. 4,786,537 (Sasaki); U.S. Pat. No. 5,695,600 (Goin); and U.S. Pat. No. 4,333,781 (Meulenberg). These prior systems each have certain disadvantages or problems, some of which are set forth below.
The computer-controlled systems of the Logan patents use complex adhesive materials including microspheres or microcapsules which, when broken by force application, release strong adhesive to allow an overlay sheet to engage and remove portions of a sheet. Such adhesives can be very expensive, and force-activation can be problematic and difficult in high-speed operations.
The Reed disclosure involves an embossing of areas to be removed in order to weaken their adhesive attachment to the base layer and facilitate removal. However, such embossing tends to be a step which, among other things, may be unacceptable for removal of intricate waste areas or patterns around irregularly shaped decals or product areas.
The Sasaki disclosure involves removal of an overlayer after a separation is caused by radiation treatment of a radiation-responsive composition. This system is complex and believed not to be suitable for many high-speed production operations.
The prior systems and disclosures fall short of offering and delivering simple, effective sheet-weeding which is fully suitable for high-speed decal production and similar waste-area removal operations.
It is an object of this invention, in the field of decal laminate technology, to provide an improved sheet-weeding method and apparatus for prior removal of waste portions of removable laminate layers which overcomes some of the problems and shortcomings of the prior art.
Another object of this invention is to provide a sheet-weeder and sheet-weeding method which can operate at high speeds.
Another object is to provide a sheet-weeder which can operate with little or no detrimental effects to the product areas remaining on the laminate.
Another object of the invention is to provide a sheet-weeding method which more reliably removes all or nearly all of the waste areas of the face layer from the backing layer while more reliably not removing all or nearly all of the product areas.
Another object of the invention is to provide a sheet-weeding which allows reliable removal of waste areas of the face layer from the backing layer around delicate products areas.
Still another object of the invention is to provide a sheet-weeder which is simple, efficient and cost-effective.
Yet another object of the invention is to provide an improved method and apparatus for removal of select areas of less-than-all layers of a laminate which are useful in a wide variety of contexts and applications.
These and other objects of the invention will be apparent from the following descriptions and from the drawings.
The invention is a method and apparatus for removing waste area(s) of a face layer from a laminate composed of a backing layer with the face layer sheet removably adhering thereto, while leaving at least one product area of the face layer in place on the backing layer. The sheet-weeding method of this invention includes applying an adhesive on portions of the waste area(s), temporarily adhering the laminate to a carrier surface (of a carrier-surface member) using the adhesive, and separating the laminate from the carrier surface with the waste area(s) remaining on the carrier surface.
A number of terms used herein are defined at the end of this xe2x80x9cSummaryxe2x80x9d section. Such definitions should be referred to for clarity of understanding.
In certain highly preferred embodiments, the carrier-surface member is a carrier sheetxe2x80x94most preferably a carrier web. In such embodiments, the adhering step, in which the laminate is adhered to the carrier web or other carrier sheet, such combination is sometimes referred to herein as a xe2x80x9ccarrier lamination.xe2x80x9d In some embodiments, such carrier lamination is discarded with the waste area(s) remaining on it. Suitable carrier web materials include unused newsprint. Embodiments using a carrier web facilitate continuous or nearly continuous sheet-weeding.
In preferred embodiments of the invention utilizing a carrier web, the process of separating the laminate from the carrier web while leaving the waste areas on the carrier web involves peeling the carrier web away from the laminate. In certain preferred embodiments, it is most preferred that the separating step include the step of pulling the carrier web over a separator edge in tension to initiate separation of the laminate from the carrier web.
As already indicated, the carrier-surface member is preferably in the form of a carrier web; however, in some embodiments it can be in the form of a fairly large cylindrical rollerxe2x80x94sufficient to accommodate various operations therearound. When in the form of a carrier web, the carrier web may be a long continuous two-ended web, such as the newsprint mentioned above, or may be an endless web each portion of which is used and reused. In preferred embodiments in which the carrier-surface member is either an endless carrier web or a large cylindrical roller, the method of this invention preferably includes, after the step of separating the laminate from the carrier surface with the waste areas thereon, the further step of removing the waste areas from the carrier surface and discarding the waste areas, thereby clearing the carrier surface for reuse.
In certain embodiments of the invention, the adhesive is applied adjacent to the product area(s), preferably only at discrete locations. It is preferred that the adhesive applicator apply a quick-drying liquid adhesive, doing so by shooting the adhesive onto the specific locations of the waste area(s) without applicator contact with the waste area(s).
Certain preferred embodiments in which a carrier web is used include: unrolling a portion of the carrier web from a roll; performing the laminating of a laminate to the unrolled portion of the carrier web; separating the laminate from the unrolled portion; and thereafter rolling up the carrier web with the waste area(s) thereon.
In preferred embodiments of this type, the web is moving in a direction along its length at least during the laminating and separating steps. In these embodiments, the product and waste area(s) each have at least one leading-edge portion and at least one trailing-edge portion (see definitions infra), some of the leading-edge portion(s) of the waste area(s) being adjacent to trailing-edge portions of the product areas. In highly preferred embodiments, the adhesive is applied to the leading-edge portion(s) of the waste areas.
In preferred embodiments, the precise locations of adhesive application are controlled by a computer. Precise locations are determined by what is best to affect separation of waste areas while leaving product areas fully intact on the backing layer.
The apparatus of this invention includes: a support for the laminate; an adhesive applicator adjacent to the supported laminate; an actuator associated with the applicator; a controller for the actuator to cause application of an adhesive to the waste area(s); a carrier-surface having a carrier surface positioned to receive the laminate with the laminate adhering thereto; and a separator adjacent to the carrier surface to separate the laminate from the carrier surface with the waste area(s) remaining on the carrier surface.
Certain embodiments of such apparatus also include a stripper for removing the waste area(s) from the carrier surface after the separation has been accomplished. This allows the carrier surface, which is preferably endless, to be reused, and in some cases enhances the continuous nature of the operation.
Certain preferred forms of the apparatus of this invention include: a work surface on which to receive the laminate; at least one adhesive applicator mounted adjacent to the work surface; an actuator associated with the applicator(s); an actuator controller to cause application of an adhesive to predetermined portions of the waste area(s); a laminator beside the work surface including a supply of carrier web oriented for temporary lamination with the laminate using the applied adhesive; and a delaminator positioned to receive the carrier lamination and delaminate the laminate therefrom with the waste area(s) adhering to the carrier web.
In certain other highly preferred embodiments of such apparatus, as already indicated by the above discussion of the inventive method, the carrier-surface member is a carrier web. In such embodiments, it is most preferred that the separator include a separator edge positioned so that the carrier web passes under tension over the edge to initiate separation of the laminate from the carrier web.
In highly preferred embodiments of the invention, the face layer of the laminate has a plurality of registration marks at and about the product area(s) which are used for locating those areas of the laminate to which adhesive is to be applied. More specifically, the apparatus includes a controller (e.g., computer) programmed with information on the product area(s) and the waste area(s) and a sensor mounted adjacent to the work surface and capable of sensing locations of the registration marks and transmitting such information to the controller. The applicator(s) is/are actuated in response to the information about the locations of the registration marks sensed by the sensor and the information on the product area(s) and the waste area(s).
The laminates for which the method and apparatus of this invention facilitate sheet-weeding operations can be in various forms. For example, the laminates can be in the form of discrete sheets, either large or small, or a laminate may be in the form of a lengthy continuous sheet (web) which extends from a supply roll to a take-up roll. Either way, the laminates to be weeded may have a large number of product areas on it, in a great variety of shapes and sizes, and a great number of waste areas in a variety of shapes and sizes. In other cases, a lengthy continuous laminate web may have one or more rows of identically-shaped product areas such as labels or the like.
Broadly considered, this invention is a method for removing sub-areas of a face layer from a laminate composed of a backing layer with the sub-areas removably adhering thereto over less than all of the backing layer, and the invention involves: applying an adhesive on portions of the sub-areas; temporarily adhering the laminate to a carrier sheet using the adhesive; and separating the sub-areas from the backing layer by peeling them off with the carrier sheet.
In certain preferred embodiments of the method of this invention, one waste area has a leading edge portion with a leading edge that includes a lead part and at least one trailing lateral part, and the separating step includes (1) separating the waste area (with the carrier surface, e.g., a carrier sheet in web or other form) from the backing layer along the lead part before the trailing lateral part(s) are separated from the backing layer, thereby creating a chord line spanning the lead part, (2) continuing the separating step until the chord line substantially spans the leading edge portion, and (3) thereafter completing the separating step.
In such embodiments, it is preferred that the leading edge portion have at least one starter tab along the lead part of the leading edge, the starter tab extending in the direction opposite the weeding direction and having a width less than about 10% of the width of the leading edge portion.
In a highly preferred embodiment, the leading edge is convex. Preferably, such convex leading edge is a substantially circular arc having a radius greater than half the width of the leading edge portion. Such arc can be very gentle; even if the radius is substantially greater than the width of the leading edge portion to the point that the arc is nearly a straight line, waste area removal is substantially facilitated.
In certain other preferred embodiments of the method of this invention, in which a product area has a delicate leading edge portion, the waste area includes one trailing edge portion adjacent to the delicate leading edge portion, such trailing edge portion having a force-modifying slit therein which surrounds the delicate leading edge portion and has ends on opposite sides thereof In certain preferred embodiments having delicate leading edge portions, the ends of the force-modifying slit are downstream of the delicate leading edge portion. Preferably, the force-modifying slit is arcuate; the slit may be substantially circular. It is highly preferred that the ends of the force-modifying slit be downstream of the delicate leading edge portion.
In certain embodiments of the inventive method, a particularly delicate product areas is surrounded by a temporary product area such that the temporary product area is removed from the backing layer at some time following the completion of the automatic weeding process.
As used herein, the following terms have the meanings given below, unless the context requires otherwise:
The term xe2x80x9cquick-drying adhesivexe2x80x9d refers to a liquid adhesive which, when applied by the applicator, flows in its liquid state easily enough to be applied with a jet applicator or sprayer but which, when applied to the waste areas of the face layer, dries rapidly enough such that it acts properly as an adhesive when it is contacted by the carrier-surface member.
The term xe2x80x9cweeding directionxe2x80x9d as used herein refers to the direction in which the weeding progresses along a sheet or roll of materia. More specifically, it refers to the direction of motion of the line along which separation of waste areas from the backing layer occurs. Accordingly, the weeding direction proceeds from xe2x80x9cupstreamxe2x80x9d positions to xe2x80x9cdownstreamxe2x80x9d positions.
The terms xe2x80x9cleading edge portionxe2x80x9d and xe2x80x9ctrailing edge portionxe2x80x9d pertain, e.g., to portions of areas of the face layer (i.e., portions of the product areas/or portions of the waste areas) in embodiments of this invention in which the carrier surface (e.g., the surface of a carrier web) is moving during the adhering and separating (or xe2x80x9claminatingxe2x80x9d and xe2x80x9cdelaminatingxe2x80x9d) steps of the sheet-weeding process. A leading edge portion of a waste area is a part thereof which is (1) immediately adjacent to and following a product area as determined along lines parallel to the weeding direction or (2) is immediately adjacent to a leading edge of the laminate if such leading edge is part of a waste area of the laminate. A trailing edge portion of a product area is a part of thereof which is immediately adjacent to and ahead of a waste area as determined along lines parallel to the weeding direction. In embodiments not involving a moving carrier web, the terms xe2x80x9cleading edge portionxe2x80x9d and xe2x80x9ctrailing edge portionxe2x80x9d refer to the order of portions undergoing separationxe2x80x94with a xe2x80x9cleading portionxe2x80x9d always being encountered before a xe2x80x9ctrailing portion.xe2x80x9d
The term xe2x80x9cleading edgexe2x80x9d as used herein with respect to a waste area refers to the line along the farthest upstream boundary of the leading edge portion of such waste area.
The term xe2x80x9cwidthxe2x80x9d as used herein with respect to a waste area refers to a dimensional measurement taken across the waste area in a direction substantially perpendicular to the weeding direction.
The term xe2x80x9cchord linexe2x80x9d as used herein refers to the line along which separation of a waste area from the backing layer takes place, with the length of the chord line being equal to the length of the continuous portion of the waste area being separated from the backing layer. Thus, if the weeding process is occurring across a wide sheet of laminate, it is possible that there could be more than one xe2x80x9cchord linexe2x80x9d defined locally along the line of separation.
The term xe2x80x9cforce ratioxe2x80x9d as used herein refers to the ratio of xe2x80x9cadhering forcesxe2x80x9d to xe2x80x9cpulling forcesxe2x80x9d on a portion of face layer. With respect to portions of a waste area which are to be separated from the backing layer, xe2x80x9cadhering forcesxe2x80x9d include both (1) the holding force of the adhesive layer (between the face layer and the backing layer of the laminate material) and (2) any additional forces from the surrounding face layer (i.e., the force exerted on the portion of waste area by the surrounding product area from incomplete slitting of the face layer and/or the adhesive layer and/or from rejoining of portions of the adhesive layer on either side of the slit) which are holding the portion of the waste area in place, and xe2x80x9cpulling forcesxe2x80x9d are adhesive forces between the waste areas and the carrier surface from the adhesive applied the waste areas. With respect to portions of a product area (not intended to be separated from backing layer), xe2x80x9cadhering forcesxe2x80x9d are the force applied by the adhesive layer between the face layer and the backing layer of the laminate material, and xe2x80x9cpulling forcesxe2x80x9d include both (1) the force exerted on the portion of the product area by the surrounding waste area being removed from around the portion of the product area (i.e., similar to the forces from surrounding waste area described above) and (2) any small forces which might occur from the contact of the carrier surface with the portion of the product area. (These force considerations are of course qualitative in nature and imply consistent bases of determination, whatever they may bexe2x80x94e.g., taking into consideration both normal forces and shear forces.)
The term xe2x80x9cdelicate leading edge portionxe2x80x9d as used herein with respect to a product area refers to a portion of the product area for which the force ratio is approximately one or less than one and which has a dimension along the weeding direction. Thus, delicate leading edge portions of product areas are susceptible to unwanted separation from the backing layer unless the force ratio is raised. Examples of delicate leading edge portions of product areas include pointed leading edge portions such as the points of a star or small shapes such as letters.
The term xe2x80x9cforce-modifying slitxe2x80x9d as used herein refers to cuts made in the trailing edge portion of a waste area adjacent to and surrounding a delicate leading edge portion of a product area to change the force ratio of the portion of the product area.
The term xe2x80x9cstarter tabxe2x80x9d as used herein refers to small areas of waste area added to leading edge portions of waste area and extending in the upstream direction from the leading edge portion in order to change the force ratio of the leading edge portion of waste area, thereby enabling initiation of the separation of the waste area from the backing layer.
The term xe2x80x9cparticularly delicate product areaxe2x80x9d as used herein refers to entire product areas which are characterized by a low force ratio.
The term xe2x80x9ctemporary product areaxe2x80x9d as used herein refers to a small area of waste area which is not separated from around particularly delicate product areas and which are separated from the backing layer by hand after completion of the automatic weeding process.